There have been proposed transition metal complex catalysts for use in the polymerization of alkene and alkyne. Such catalysts are, for example, complexes having the following formulas: ##EQU1## wherein .PHI. is phenyl group, R is an alkyl group of 1 to 3 carbon atoms or an aryl group such as phenyl, tolyl, xylyl or naphthyl, and X is Cl, Br or I.
Such complex catalysts may be prepared by the reaction of tetrakis(triphenylphosphine(nickel or .alpha.-dipyridyl(dialkyl)nickel with halogenated compound as follows: ##EQU2##
The complex catalysts having the formulas (I) and (II) are objectionable in that they are thermally decomposable. Accordingly, these catalysts cannot be recovered after they have been used as a catalyst in the polymerization, i.e. they are very difficult to use repeatedly.
It is, therefore, an object of the present invention to provide thermally stable catalysts for use in the polymerization of alkene and alkyne.